Most of the water supplied in New Zealand is slightly acidic. Acidic water is also known as plumbosolvent water – this means it dissolves lead and other heavy metals.
The Ministry of Health believes that the risk from heavy metals in drinking water is small. However, as a precaution, it recommends that all households flush a glass (500ml) of water from their drinking water tap each morning to eliminate the risk.
Plumbosolvency is the ability of a solvent (usually a liquid) to dissolve other substances.
Plumbosolvent water can dissolve any metals that it comes into contact with. If it is left sitting for several hours in your household plumbing fittings, small amounts of heavy metals from these fittings can enter the water supply.
Heavy metals commonly dissolved in drinking water include lead, nickel, cadmium and copper.
No. This is not about the chemical quality of your drinking water but about whether the water has had prolonged contact with metals in household plumbing fittings.
We continue to meet the requirements of the Drinking Water Standards for New Zealand 2005 (revised 2008) and deliver safe water that you can use from your taps each day.
Under the Drinking Water Standards for New Zealand 2005 (revised 2008), the Ministry of Health requires water suppliers to alert residents to the issue of plumbosolvency. For water suppliers serving more than 1000 people, such as Watercare, this is done twice a year through a public notice from the Ministry of Health.
Water supplies are considered to be plumbosolvent until the water supplier can show otherwise.
Read our water quality reports
Heavy metals are a health concern whether they come from drinking water, air or food. They can build up in the organs of your body. High levels can be harmful to your health.
Infants, children and pregnant women are more susceptible to the toxic effects of heavy metals, so steps should be taken to reduce heavy metal concentrations in water that this group of people may consume.
Lead is the main heavy metal in drinking water and the one that poses the greatest health concern. Lead cannot be removed from the body, so it builds up in the skeleton and can damage nerves and organs. Infants, children and pregnant women are most susceptible to lead's toxic effects, which can include brain and kidney damage.